Sample spreadsheet
shows an extract of a sugar subsequence to illustrate the
principles involved. Creating subsequences which is
controlled by a main sequence is easily achieved. Using this
principle gives us instant visibility of the whole program
by monitoring main and associated sub sequences. The
Illustrated PLC code shows
the translation between the spreadsheet and the ladder
logic.

Since the introduction of the Rockwell
Automation ControlLogix PLC system, the use of user defined data types have been
probably the best thing to have happened to ladder logic in
years. Effectively structuring user defined data types leads
to embedding the labels as the memory location for the tags.
This vastly improves visibility of data as the storage
location is the label. We have standardised on useful data types that helps code
development dramatically. Again please
contact us for
details.